The present invention is directed to a grommet, and more particularly to a self-sealing grommet assembly.
Flexible grommets are often used in an aircraft or the like to provide a seal between a hole in a wall panel and the outer diameter of a wire bundle, cable, or tube. Conventional grommets provide suitable performance characteristics when the wire bundles, cables, or tubes have consistent diameters within fairly tight tolerances. When a wire bundle, cable, or tube has an irregular diameter at various positions along its length, it is much more difficult to maintain the seal with a conventional grommet. Also, grommets can be worn out or eaten by fluids so as to degrade sufficient surface contact with the wire bundle, cable, or tube over the life of the grommet. It is highly desirable in many controlled environments to provide and maintain a seal with the grommet to prevent liquids, dust, debris, gasses, etc. from passing through the wall panel while still enabling the wire bundles, cables, or tubes to extend through the wall panel.
The present invention overcomes limitations of the prior art and provides additional benefits. A brief summary of some embodiments and aspects of the invention is presented. Thereafter, a detailed description of the illustrated embodiments is presented, which will permit one skilled in the relevant art to make and use aspects of the invention. One skilled in the art can obtain a full appreciation of aspects of the invention from the subsequent detailed description read together with the figures, and from the claims that follow the detailed description.
Under one aspect of the invention, a grommet assembly is provided that comprises a flexible body portion having a radially inward-facing first sealing surface defining a central aperture sized to receive an elongated member, such as a cable, wire bundle, tube, or the like. The flexible body portion has a radially outward-facing second sealing surface spaced apart from the first sealing surface, and an annular cavity is in the body portion between the first and second sealing surfaces. The annular cavity is substantially concentric with the central aperture. A biasing member is contained within the annular cavity and is configured to exert a radially inward sealing force that biases the body portion into a sealable engagement with the elongated member.
Under another aspect of the invention, the grommet assembly is adapted to fit into an aperture in a structure, such as a wall or panel through which the elongated member extends. The grommet assembly includes a second biasing member contained in the annular cavity and configured to exert a radially outward sealing force that biases the body portion into sealable engagement with the structure.
Under another aspect of the invention, a grommet assembly is made by the process including encasing a biasing member in a soluble core material to form a generally annular core. A flexible material is molded around the annular core to form a grommet. The grommet has a grommet body with a radially inward-facing first sealing surface defining a central aperture and a radially outward-facing second sealing surface generally concentric about the first sealing surface. The annular core is encased within the grommet body between the first and second sealing surfaces to form an annular cavity within the body portion. A flow of solvent is directed into the annular cavity, and the core material is dissolved within the annular cavity by the solvent. The solvent and the dissolved core material are removed from the cavity while the annular-shaped biasing member remains in the annular cavity. The biasing member is configured to exert a radially inward or outward sealing force that biases the body portion into sealable engagement with an elongated member or a structure.